Guide
How the kit works
Before a fight, use From Façade to Vérité. At the start of the next battle it attempts to apply Arcana repeatedly to each enemy, starting at a 150% base chance and halving that chance after each success. Goblet's Dredges also has a chance to apply Arcana and the Skill’s DEF reduction when an enemy enters combat.
Loom of Fate's Caprice gives each instance of DoT received by an enemy a 65% base chance to inflict one Arcana stack. Arcana counts as Wind Shear, Bleed, Burn and Shock. It deals Wind DoT equal to 240% of Black Swan’s ATK at the start of each turn, with each stack adding 12% to the damage multiplier. Arcana damage ignores 20% DEF. When it deals damage at the start of an enemy’s turn, adjacent enemies take Wind DoT equal to 180% of her ATK.
Viscera's Disquiet gives Black Swan’s attacks a 65% base chance to inflict five Arcana stacks. Use Decadence, False Twilight to hit a target and adjacent enemies for 90% of her ATK, with a 100% base chance to lower their DEF by 20.8% for three turns. Percipience, Silent Dawn hits one enemy for 100% of her ATK. Goblet's Dredges also gives her Basic and Ultimate a chance to apply the Skill’s DEF reduction to enemies hit.
Use Bliss of Otherworld's Embrace to apply Epiphany for two turns and hit all enemies for 120% of her ATK. Enemies in Epiphany take 25% more damage, and each Arcana stack inflicted has a 50% fixed chance to add another stack in that application. Arcana normally halves after its start-of-turn damage, but it does not halve while the enemy is in Epiphany. It can exceed its 50-stack limit, with excess stacks removed after damage.
Build and why
Use four pieces of Prisoner in Deep Confinement. Its two-piece ATK bonus helps Arcana damage, and the four-piece effect ignores 6% DEF for each DoT on the target, up to three. Eagle of Twilight Line is another option if you want Wind DMG and an action advance after the Ultimate.
For the planar set, use Revelry by the Sea. It gives ATK and increases DoT damage by 12% at 2400 ATK or 24% at 3600 ATK. Pan-Cosmic Commercial Enterprise is another good option: it gives Effect Hit Rate and converts some of that stat into ATK.
Reforged Remembrance is the first Light Cone to look for. Its Effect Hit Rate helps Black Swan’s application chances, while Prophet stacks give ATK and let her DoT ignore DEF. Arcana counts as the four DoT types that Prophet checks. Those Many Springs is another option for Effect Hit Rate and its chance to make attacked enemies take more damage. Eyes of the Prey is a 4-star option with Effect Hit Rate and increased DoT.
Use Effect Hit Rate on the body, ATK Percentage or SPD on the feet, Wind DMG Boost on the sphere and ATK Percentage on the rope. For substats, the game’s build puts ATK Percentage first, then Effect Hit Rate and SPD. Candleflame's Portent gives allies damage equal to 60% of Black Swan’s Effect Hit Rate, up to 72%, so that part reaches its cap at 120% Effect Hit Rate.
Leveling priority
Follow the game’s order: Loom of Fate's Caprice, Percipience, Silent Dawn, Decadence, False Twilight, then Bliss of Otherworld's Embrace. Talent comes first because it contains Arcana’s damage and stacking rules. Basic is next for its direct damage, followed by Skill and Ultimate.
For maximum ascension, you need 308,000 Credit, 65 Ascendant Debris, 15 Extinguished Core, 15 Glimmering Core and 15 Squirming Core.
For all skills, gather 3,000,000 Credit, 8 Tracks of Destiny, 18 Fiery Spirit, 69 Starfire Essence, 139 Heaven Incinerator, 12 Past Evils of the Borehole Planet Disaster, 41 Extinguished Core, 56 Glimmering Core and 58 Squirming Core.
Eidolons worth it
As a suggestion, Pantheon Merciful, Masses Pitiful looks like the largest jump. It raises the Arcana limit by 30, gives teammates’ attacks a 65% base chance to apply a stack and adds one stack for every stack Black Swan inflicts.
Next, Weep Not For Me, My Lamb gives a 100% base chance to inflict 30 Arcana stacks when enemies enter combat. Seven Pillars of Wisdom is also worth considering: while Black Swan is active in combat, it reduces the corresponding Wind, Physical, Fire or Lightning RES by 25% for enemies affected by those DoT types. Arcana counts as all four.
In Tears We Gift adds 20% damage taken during Epiphany and lets Black Swan recover 8 Energy at the start of every turn or when an affected enemy is defeated. If you are stopping earlier, you can pass on As Above, So Below or Linnutee Flyway: they raise skill levels rather than add a new effect.
Common mistakes
Do not treat a 100% base chance as a guaranteed application. Effect Hit Rate helps with Black Swan’s chance-based effects, so do not ignore it while chasing ATK. The 120% point caps her passive’s team damage bonus, not necessarily the usefulness of more Effect Hit Rate for applying effects.
Do not assume Arcana stacks stay intact without Epiphany. They normally halve after start-of-turn damage, and stacks beyond the limit are removed after damage. Watch the enemy’s Epiphany state when building stacks instead of expecting every stack to carry over.
